A method has been devised for entirely eliminating nerve and interstitial cells from the freshwater coelenterate, hydra. The method involves treatment with high concentrations of colchicine. The resulting animals will be studied to see which aspects of pattern formation and morphogenesis can take place in the absence of nerves. Nerve cells in hydra are considered important to development, as they are in regeneration of higher animals; our ability to remove nerve cells from hydra makes it possible to study intensively the developmental roles of nerves in ways difficult or impossible in higher animals. BIBLIOGRAPHIC REFERENCES: Campbell, R. D. (1976) Elimination of Hydra interstitial and nerve cells by means of colchicine. J. Cell Science. 21: Marcum, B. A. and Campbell, R.D. (1976) Development of hydra lacking nerve and interstitial cells. American Zoologist (Abstract).